Foil applique structure



y 1963 J. A. COLFER ET 3,089,800

FOIL APPLIQUE STRUCTURE Filed Oct. 7, 1958 James J. Collins,

James A. Co'lfer,

INVENTORS.

' ATTORNEY.

- on either or both surfaces thereon. is then applied to one of saidsurfaces and a protective sited rates The present invention relates toetched sheet metal objects and to a method for the manufacture thereof.More particularly the invention relates to aluminum sheets or foilswhich are provided with predetermined patterns and which are cut out andcan be completely free from supporting background, for use particularlyas metal appliques, stencils, or the like.

The etching of metals to form patterns or insignia thereon is in generalwell known. Such methods usually include the steps of forming a patternor resist thereon adapted to resist etching agents, and subjecting thesheet to the action of etching or metal dissolving agents, such as acidsor alkalies to dissolve away the unprotected metal. Aluminum in the formof sheet or foil is frequently utilized to form ornamental or otherobjects, such as labels and the like, particularly in the oxidized oranodized form in view of the receptivity of the oxidized film to dyes,pigments and other coatings. One method of utilizing aluminum in thismanner is described in US. Patent 2,769,265. In general, such productsare obtained by utilizing alkaline or acid solutions, however applicantshave found that the anodized film, which is composed of aluminum oxide,is resistant to alkaline baths as well as certain acid solutions andthus particular acid materials are preferably utilized to etch or removethe oxidized surface from the aluminum prior to dissolution of themetal. On the other hand, it has been found preferable to utilizealkaline solutions or certain acid solutions for the etching or chemicalmilling of aluminum in order to obtain the most effective results.Certain other problems exist in the etching of aluminum sheet or foildue to the necessity for obtaining a clean etch which will not undercutthe resist areas and which will result in a clean cut and well definedpattern without ragged edges.

Applicant has discovered a novel method for the manufacture of etchedaluminum objects particularly applicable to the formation of stencilsand cut out ornamental patterns without any metallic background fromoxidized or anodized sheets or foils of aluminum. The process is carriedout by providing a sequence of operations starting with sheets ofaluminum having an oxide film formed The resist pattern layer is appliedto the surface opposite to that having the design thereon. Theunprotected surface areas which are not covered with a resist design arethen subjected to an acid treatment, preferably with dilute hydrofluoricacid,

for the purpose of removing the oxide film from the exposed surfaces.After this treatment, the exposed metal is then etched through to theinner surface of the oxide film on the other side of the sheet using anydesired etching solution which will suitably dissolve aluminum withoutundercutting or forming ragged edges. Such solutions may be of acid oralkaline nature and dilute HCl solutions or concentrated solutions ofNaOI-I have been found suitable. The oxide layer on the other surface isthen removed by again etching in an acid solution, such as dilute HFtocomplete the chemical milling through the sheet. When the protectivebacking is removed, the design is thus exposed for use. Preferably thedesign is applied as a resist in reverse so that after the etch iscompleted, the side opposite that to which the design was appliedrepresents the positive of the design pattern. When a on is coloredproduct is desired, the anodized sheet is dyed or otherwise colored orpigmented, at least on the surface opposite to that to which the designis applied, so that on reversing the final etched product, the coloredsurface represents the desired pattern. By applying an adhesive, such asa pressure sensitive adhesive, plus a backing sheet, to the exposedsurface of the etched product, the stencil or cut out member can behandled with both surfaces protected by sheet material until use, atwhich time the reverse surface may be exposed by removal of the sheetaffixed thereto, the adhesive can then be bonded to the desired surface,and the protective sheet on the other surface can then be removed toexpose the desired pattern. Of course other types of adhesives may beused, such as those activated by water or organic solvents as Well knownin the art.

It is, therefore, an object of the present invention to provide a novelornamental structure or stencil of sheet aluminum having cut out areasformed therein in which the outer surfaces of the sheet are composed ofcolored or uncolored anodized or oxidized aluminum.

It is a further object of the present invention to provide a method forthe manufacture of sheet or foil aluminum objects having cut out areasin which clean cut and faithful patterns are obtained in a simple andeffective manner.

Other objects will become apparent from a consideration of thespecification and drawings which are further described below.

In the drawings:

FIG. 1 is a detail view partly in cross section and partly in elevation,illustrating the structure of an anodized sheet preparatory toprocessing in accordance with this invention.

FIG. 2 is a view corresponding to FIG. 1 except that the anodizedsurface of the sheet is pigmented by dye or otherwise.

FIG. 3 illustrates the application of a resist design to a surface ofthe sheet of FIG. 1.

FIG. 4 illustrates the structure of FIG. 3 with a protective layerapplied to one surface thereof.

FIG. 5 is a view in cross section taken along lines 5-5 of FIG. 4,showing the surface of the structure of the element after the first acidetch step to remove surface oxide film.

FIG. 6 is a view in tranverse cross section taken along a planecorresponding to line 55 of FIG. 4 illustrating the structure of theelement after the metal of the sheet has been dissolved through,subsequent to the initial surface etch.

FIG. 7 is' a view taken along a plane corresponding to line 55 of FIG. 4showing the structure of the element after the second acid etch toremove the oxide layer adjacent to the protective film.

FIG. 8 is a view in elevation illustrating the application of anadhesive film to the upper surface of the etched product.

FIG. 9 is a view in cross section taken along line 9-9 of FIG. 8,showing the structure of the assembled unit prior to application to anobject.

FIG. 10 is a view partly in elevation and partly in cross sectionillustrating the application of the final etched and cutout product to asurface and the removal of the protective film therefrom.

As shown in FIG. 1, a sheet or foil member 20 of aluminum is formed bycoating the aluminum body portion 21 with a layer of aluminum oxide 22and 23 on surfaces 18 and 19 respectively by a suitable oxidationtreatment generally 'known as anodizing. As shown in FIG. 2 the anodizedsheet of FIG. 1 is preferably pigmented by dyeing or otherwise treatingone or both of the anodized surfaces. As shown in FIG. 2, the anodizedlayer 23 of the sheet 20 is pigmented with a dye shown at 24.

A resist pattern 25 having a predetermined design is applied to thesurface of the anodized layer 22 of the sheet 20. If desired, only onesurface of the sheet 20' may be anodized and the resist pattern appliedto that surface which is not so treated. In general, however, the oxidefilm is formed on both surfaces. By the same token, the pigment may beomitted so that the surface opposite the resist will possess the normaloxidized coloration. Where the design is intended to have a particularconfiguration as in the case of lettering or the like, it is preferablyapplied to the intended surface in reverse. One commonly utilized methodis to form a suitable plate by photographic or other conventional meansand then printing in reverse on the said surface utilizing a lacquer orpolymer type of ink which will resist the action of acid and alkalinesolutions to which the foil is to be subjected. After the application ofthe resist pattern, which is illustrated in FIG. 3, a protective layer26 is applied to the bottom surface of the sheet 20 opposite to thesurface to which the resist is applied as shown in FIG. 4. The purposeof the protective layer 26 is to protect the bottom surface against theaction of the etching fluids to which the product is to be subjected. Inorder to permit ready removal to expose the surface of the finalproduct, this protective layer is preferably applied in the form of asheet material such as paper, plastic film, or fabric, applied to thesurface with an adhesive which may be of the temporary or pressuresensitive type, or which may permit delamination or removal of the layerthrough the use of a solvent or softening agent. Such protectivebackings are well known in the prior art as represented, for example, byU.S. Patents 2,629,679, 2,647,849, 2,567,067, and 2,532,011.

At this point the element is immersed in a suitable acid bath for thepurpose of etching around the resist pattern to remove only that portionof the oxide film layer 22 which is exposed, that is, not covered by theresist 25. Preferably this bath is composed of a dilute solution ofhydrofluoric acid although other suitable acid materials may beutilized. HF concentrations of about 10% to 20% have been foundsatisfactory. This treatment results in the delineation of the pattern25 by removal of that portion of the oxide layer 22 which is exposed tothe acid. In cases where the oxide film is formed only on the surface ofthe sheet 20 opposite the resist, this etching step may be eliminated.

When the exposed portions of the oxide layer 22 have been removed, asshown in FIG. the assembled unit is thoroughly rinsed to remove anytraces of hydrofluoric acid and then introduced into an etching orchemical milling bath, which may be either chemical or electrolyic forthe purpose of removing the aluminum metal which has now been exposed atthe surface by the removal of the oxide. This treatment then serves toremove the aluminum so exposed, as shown in FIG. 6, further deepeningthe etch in conformity to the resist pattern which is unaffected.Suitable etching or chemical milling solutions particularly adapted foretching or chemical milling of metallic aluminum are dilute hydrochloricacid or concentrated alkali solutions. Such solutions include to 30% HClor saturated or supersaturated NaOH solutions used at elevatedtemperatures. Such solutions are effective for metallic aluminum, butare not desirable for the removal of aluminum oxide films.

The unit is then thoroughly washed to remove any traces of the alkalineor acidic etching solution and is then again immersed in a solution ofhydrofluoric acid for the purpose of removing that portion of the oxidelayer 23 which has been exposed by removal of the aluminum as shown inFIG. 6. This is carried out in a solution similar to that used inconnection with the discussion of the step illus trated in FIG. 5. Theproduct then consists of a completely cut out foil member having onesurface thereof covered by the protective layer 26 as shown in FIG. 7.At this point, the ornamented or patterned surface of the unit consistsof the cut out letters conforming to the design selected, for purposesof illustration, which in turn are supported upon protective layer orsheet member 26. The resist is removed by immersing the unit into asuitable solvent thus exposing layer 22. The unit is then thoroughlywashed to remove any traces of HF on the exposed surface of the patternor design. The surface of the remaining portion of layer 22 is thencoated with a layer of adhesive preparatory to application to thesurface to which it is to be affixed. Preferably the unit is coated witha layer of pressure sensitive adhesive overlaid with a protective sheetor film which may be removed, leaving the adhesive behind, when the unitis to be applied. Thus, as shown in FIG. 8, an adhesive 28 may be firstapplied to a carrier sheet 27 which is laid over the surface of the cutout design. Preferably this sheet may be of such a nature that theadhesive is transferred to the surface of the patterned unit when thecarrier sheet is removed. If desired, a suitable adhesive may be applieddirectly to the surface of the cutout design and then a sheet ofnonadherent material applied thereover for the purpose of protecting theadhesive surface to be used. Such types of sheet material are well knownto the prior art and generally composed of paper or the like, coated orimpregnated with a mate rial having little or no cohesive properties forthe adhesive utilized as shown, for example by U.S. Patent 2,532,011.The resulting assembly then consists of a sheet backing and protectivemember 26, the cut-out foil or sheet pattern 30 superimposed thereon,and a protective or release sheet 27 having adhesive 28 on the othersurface thereof overlying the patterned surface which is still inreverse. This assembly is illustrated further in FIG. 9 in crosssection.

When the assembly is ready for use, the upper surface of the cutoutpattern 30 is exposed by removing sheet member 27, leaving adhesive 28on the exposed surface of the pattern. The member is then laid with theadhesive side down against the surface of the object 29 to which thepattern is to be applied, as shown in FIG. 10. In this way, a positiveview of the pattern is obtained since the reverse side is down againstthe object to which it is applied as shown. As illustrated in FIG. 10,patterned material is adhered to the surface of an article 29 in themanner described, then the protective sheet mem ber 26 is removedthereby exposing the pattern or de sign in its desired positive form.

The sheet or foil utilized in making the appliques of this invention isof any desired thickness, although for best results, the material iswithin the range of 0.002 to 0.010 inch in thickness. The anodized filmis of variable depth depending on the nature and extent of thetreatment, but generally the oxide film thickness or depth should be atleast 0.0001 to about 0.0004 inch in order to obtain satisfactory dye orpigment and color and uniformity. The manner in which the anodized filmis obtained is well known in the art as exemplified by U.S. Patent2,769,265 described above.

It is obvious that various changes and modifications may be made in thedetails of procedure and construction described herein without departingfrom the spirit of the invention.

I claim:

1. An individual applique separable from others with which it may bemanufactured, for individual use on a desired surface to which it is tobe adhered, said applique comprising the combination of: a metal foilhaving a predetermined configuration; a release sheet of protectivedisposable material; a first adhesive coating on said release sheetadhering one side of said foil to said release sheet, said firstadhesive coating being less tenacious to said release sheet than to saidfoil whereby to coat said foil for adhesion to said desired surface uponremoval of said release sheet; a protective sheet of disposablematerial; and a second adhesive coating adhering said protective sheetto the other side of said foil, said second adhesive coating providing abond to said protective 5 sheet which is weaker than the bond providedbetween said foil and said desired surface and stronger than the bondprovided between said foil and said release sheet by said first adhesivecoating.

2. An individual applique separable from others with which it may bemanufactured, for individual use on a desired surface to which it is tobe adhered, said applique comprising the combination of: an aluminumfoil having an oxide coating on at least one surface thereof andcomprising a predetermined configuration; a release sheet of protectivedisposable material and of greater area than said foil; 2. firstadhesive coating on said release sheet adhering one side of said foil tosaid release sheet, said first adhesive coating being less tenacious tosaid release sheet than to said foil whereby to coat said foil foradhesion .to said desired surface upon removal of said release sheet; aprotective sheet of disposable material of greater area than said foil;and a second adhesive coating adhering said protective sheet to theother side of said foil, said second adhesive coating providing a bondto said protective sheet which is weaker than the bond provided betweensaid foil and said desired surface and stronger than the bond providedbetween said foil and said release sheet by said first adhesive coating.

References Cited in the file of this patent UNITED STATES PATENTS

1. AN INDIVIDUAL APPLIQUE SEPARABLE FROM OTHERS WITH WHICH IT MAY BEMANUFACTURED, FOR INDIVIDUAL USE ON A DESIRED SURFACE TO WHICH IT IS TOBE ADHERED, SAID APPLIQUE COMPRISING THE COMBINATION OF: A METAL FOILHAVING A PREDETERMINED CONFIGURATION; A RELEASE SHEET OF PROTECTIVEDISPOSABLE MATERIAL; A FIRST ADHESIVE COATING ON SAID RELEASE SHEETADHERING ONE SIDE OF SAID FOIL TO SAID RELEASE SHEET, SAID FIRSTADHESIVE COATING BEING LESS TENACIOUS TO SAID RELEASE SHEET THAN TO SAIDFOIL WHEREBY TO COAT SAID FOIL FOR ADHESION TO SAID DESIRED SURFACE UPONREMOVAL OF SAID RELEASE SHEET; A PROTECTIVE SHEET OF DISPOSIBLEMATERIAL; AND A SECOND ADHESIVE COATING ADHERING SAID PROTECTIVE SHEETTO THE OTHER SIDE OF SAID FOIL, SAID SECOND ADHESIVE COATING PROVIDING ABOND TO SAID PROTECTIVE SHEET WHICH IS WEAKER THAN THE BOND PROVIDEDBETWEEN SAID FOIL AND SAID DESIRED SURFACE AND STRONGER THAN THE BONDPROVIDED BETWEEN SAID FOIL AND SAID RELEASE SHEET BY SAID FIRST ADHESIVECOATING.